Drier for sand, gravel, etc.



W.H.DANCE May 21, 1929.

DRIER FOR SAND, GRAVEL, ETC

Filed Sept. 19, 1928 uHu rnllllll llv l I Lin: 0} l urizanfal .J'a mrf Patented May 21, 1929.

WILLIAM H. DANCE/OF CAMBRIDGE, MASSACHUSETTS.

DRIER FOR SAND, GBAVEL, ETC.

Application filed September19, 1928. Serial No. 306,928.

This invention relates to a drier compris ing an elongated open-ended drum mounted to rotate on an inclined axis, and provided with a series of longitudinally extending 1nwardly projecting fianges, known. as fells,

adapted to alternately raise and release loose material fed into the higher end ofjthe drum, and a fixed hydrocarbon burner arranged to project flame into the lower end of the drum 1 toward the higher end, the materlal alternately raised and released in the drum being caused by the inclination and rotation or the drum to move in an approximately helical path from the higher to the lower end and discharged at the latter, the material being dried by the heat generated bywthe burner; The vapor liberated from the ma terial and theproducts of combustion escape from the higher endof the drum through. a stack provided for that purpose.

' It is very desirable in a drier of-this character that the material being. driedbe prevented from dropping through and contacting with the burner flame, such contact cans ing the material to take up unconsumed 011.

The present invention has for its object to provideimproved means for preventing contact of the dropping material with the burnor flame, the nature of said means being such less liability to deterioration or damage by the heat generated by the burner.

Of the accompanying drawings forming a part of this specification,-

Fi re 1' is a. side elevation of a drier embodying the invention, a portion of the elongated drum hereinafter described being broken away. a I

Figure 2 is a fragmentary vperspective view, showing a portion of the inner drum hereinafter described.

Figure 3 is a section on line 33 of Figure 1. V I a Figure 4 is a section on line 4 4 of Fig-: ure 1. V v 1 The same reference characters indicate the same parts in all of the-figures.

In the drawings,.12 designates an elongated open-ended drum, mounted to rotate on an inclined axis. In this instance, the drum 7 that the drier is adapted to dry loose materi-' al more rapidly than heretofore, and with is supported by rollers, journaled in bearings on an inclined supporting frame 13, the drum being provided with peripheral grooved tracks bearing on the rollers. One

roller 14 and one track l5 are shown by Figure 1 and it is tovbe understood that i the drum will be provided with two or more spaced apart tracks, and that each track bearson two rollers. r Thedrum may be rotated by a driving gear (not shown) meshing with a geartoothed ring 16 surrounding the drum. At the higher end of the drum is a fixed head 17 covering said end and supporting a stack 18, and a chute 19, arranged to feed material into the higher end, the head, stack and chute being supported a frame 20.

The drum 12 has a series of longitudinally extending inwardly projecting flanges 21, which I call distributing fells. These are adapted to alternately raise and release loose material fed into the drum by thechute 19,

the fells extending from end to end of the drum. 22 designates somewhat conventionally, a fixed burner arranged to project flame into the lower end of the drum toward the higher end, the'burner being supported by a fixed frame 23. r

The structurethus far described is well known and is adapted. to circulate loose ma-. terial fed into thehigher end of the drum and cause the material to progress in an approximately helical path from the higher to the lower end of the drum.

In carrying out my invention, I provide the improved means nextdescribed for additionally circulatingand drying the material andpreventing contact .thereof'with the burner flame, said means characterizing the invention. V

25 designates an inner drum which is shorter and of smaller diameter than the longer drum 12, and is fixed to the longer drum within the lower end portion thereof. The outer end of the drum 25 is substantially flush with the lower end of the drum -12. The burner is preferably adapted to project a flame about four feet long, and the length of the inner drum 25 is such that it surrounds the entire length of the flame.

Any suitable means may be employed to gered relation thereto.

secure the inner drum to the lower end portion of the drum 12 in such manner as to maintain the drums substantiallyconcentric with each other and separated by an annular space 26. In this instance I provide the inner drum with outwardly projecting arched brackets 27, whose outer ends are fixed to the tells 21 ot the drum 12, preterably by angle strips 28, constituting extensions of the tells 21, as shown by Figure l, each fell 21 being thus adapted tohold, raise and release a mass of loose material.

The inner drum isprovided with a series of outwardly projecting distributing tells 29, each preferably of the channelled term shown by Figures 2 and 4:, the tells 29 alternating with the tells 21, and being in stag- The annular space 26 contains the tells 29 and the end portions of the tells 21. The arrangement is such that material distributed in themain portion otthe drum12 by the tells 21, enters the space 26, is distributed therein by the two seriesof tells, without contact with the burner flame, is acted on in-all parts ct said space'by heat radiated from the. inner drum, and is discharged from the outer end of the drum 12.

The drums are rotated in the direction of the arrow w, preferably about nine times per minute. Each fell portion 21ext-ended by the angular strips 28, raises material from V the bottom of the space 26, and spillsthe inaterial against the heated external surface of the inner drum. The gravitating material is caught by ascending tells 29,-which in turn alternately raise and spill the material. It will be seen therefore that the circulating material-moves in a zigzag, as Well as a helical path in the space 26, and has a maximum exposure. to heat radiatedfrom the outer surface of the inner drum.

I have found by practical experience, that a drier characterized as above described, is capable of drying materialmuch more rapidly thaniany other drier of which I am aware, because of the described peculiar circulation of the material in the space 26, and ot the extended heat radiating surface provided by the inner drum. Moreover, I have found that the inner drum entirely surrounding'the flame. and rotating with the drum .12 is less liable. to be warpedand distorted by the heat of the burner flame than any other means known to me for preventing contact ot the circulating material with the burner flame. The operative life ofthe drier is therefore increased and the delay and expense incidental to repairs are reduced To further increase the period of usefulness of the inner drum, 1 locate the burner 22 eccentrically relative to the axis of the drums 12 and 25 (said drums being coaxial), so that one side portion of the inner drum is nearer the burner flame and receives more heat therefrom than the opposite side portion. The rotation of the drums causes a continuous interchange of said drum portions, so

that the more highly heated portions recede from the tlanie and part with a portion ot their heat before again approaching the flame. Excessive heating of any portion ot the inner drum is thus prevented, and the heat is effectively distributed in the space 26.

The inner drum may be provided at its outer: end with an annular baflie flange 31, preterably ot the tapering or flaring torm shown by Fi ure 1, said flange partly closing or obstructing the outer end ot the annular space 26, and limiting the escape of dust frointhe said space, and particularly the upper portion thereof where the escape is naturally greatest.

The batlie tlangedetlects dust tending to escape from the upper portion otthe space 26, and causes it to pass downward and be discharged from the drum 12 with the coarser dried material, so that the dust, or the major portion thereof, is utilized as a part of the dried product.

I claim:

1. A device of the character stated, comprising an elongated open-ended drum,

mounted to rotate on an inclined axis, and

having a series of longitudinally extending inwardly projecting distributing tells, adapted to alternately raise and release loose material fed into the higher end of the drum, and atixed burner arranged to project flame into the lower end of the drum toward the higher end, the drier being characterized by an inner drum which is shorter and of smaller diameter than the longer drum, and is fixed to the longer drum within'the lower end portion thereof, the inner drum havinga series of longitudinally extending out- 'wardly projecting distributing fells alternating with, and in staggered relation to the inwardly projecting tells of the longer drum, the inner drum being proportioned and arranged to entirely surround and be heated by the flame projected by the burner, and separated from the lower end: portion of the longer drum by an annular space containing the inner drum tells and end portions of the longer drum tells, the arrangement being such that material distributed by the tells of the longer drum enters said space, is dist'ibuted therein by the two series of tells, without contact with the burner flame, is acted on in all parts of said space by heat radiated'trorn the inner'drum, and is dis charged from the outer end of the outer drum. i

2. Adrier asstated by claim 1, the burner being eceentrically located relative to the axis of the drums, so that one side portion of the inner drum. is nearer the. burner flame, and receives more heat than the op fixed to the inwardly projecting fells of the 10 posite side portion, the rotation of the drums longer drum. causing a continuous interchange of the said 4. A drier as stated by claim 1', the outer drum portions and preventing excessive end of the inner drum being provided With heating of any portion of the inner drum. an annular bafiie flange, partly obstructing 3. A drier characterized as stated by the outer end of the said annular space. '15 claim 1, the inner drum being provided with In testimony whereof I have affixed my outwardly projecting brackets, alternating signature.

with the outwardly projecting fells, and WILLIAM H. DANCE. 

